Roller cone drill bits are used to form wellbores in subterranean formations. Roller cone drill bits generally include at least one support arm and often three support arms. A respective cone assembly may be rotatably mounted on interior portions of each support arm. Each cone assembly may include a base with a cavity formed therein. Each cone cavity may be sized to receive exterior portions of a journal or spindle to allow rotation of the cone assembly relative to the journal or spindle while drilling a wellbore. A wide variety of bearings, bearing assemblies, bearing surfaces, seals and/or other supporting structures may be disposed between interior portions of each cone assembly and exterior portions of the journal or spindle.
Roller cone drill bits may further include lubricant systems to supply lubricant to journals, bearings, bearing assemblies, bearing surfaces, seals and/or other supporting structures associated with rotation of each cone assembly mounted on a respective support arm. A variety of lubricants may be used with roller cone drill bits to accommodate rotation of each cone assembly relative to the respective spindle. A wide variety of seals and seal assemblies may be used to prevent leaking of lubricants, prevent contamination from downhole well fluids entering the interior of each cone assembly, and/or maintain lubricant system pressure.